Cardiovascular disease (CVD) remains the leading cause of death in older adults. Statins are highly effective cholesterol-lowering medications used for primary prevention of CVD, and are the most commonly prescribed medications. After age 75, data on the effects of statins are limited to guide statin prescribing recommendations. However, even where the evidence is clear, statins remain under-prescribed. Reasons for under-prescribing of proven CVD prevention medications such as statins in older adults are many, and may include competing medical conditions, adverse side effects (e.g., myalgias), and frailty. Frailty is a multidimensional state of decreased physiologic reserve associated with an increased risk of CVD and poor clinical outcomes. The aging population is heterogeneous and a one-size fits all approach may not be appropriate. In particular, understanding the utility of statins for prevention of CVD in individuals who are vulnerable or frail is critical. Therefore, the research activities in this GEMSSTAR award will use a retrospective design to (1) understand patterns of statin use in a large cohort of older US veterans aged 65 and older, over 15 years of follow up, with particular attention to the relationship between frailty, myalgias and statin use; and (2) examine the association between statin use for primary prevention of CVD in pre-frail and frail older veterans and cardiovascular events, health care utilization, and mortality. This work will inform the design of future clinical trials of statins for prevention of CVD in older adults accounting for heterogeneity of aging and frailty. In addition to the pharmacoepidemiologic study proposed, this GEMSSTAR award includes mentorship, coursework, and seminars in advanced epidemiologic and statistical methods, geriatrics, and cardiology. The research and career development activities will prepare the applicant for her long-term goal of a research career in geriatric preventive cardiology and will inform preventive care for the aging population.